Ors to the society of chemical industry in basle



UNITED STATES PATENT ROBERT ,GNEIIM AND JAKOB SCHMID, OF BASLE, SIVITZERLAND, ASSIGN- ORS TO THE SOCIETY OF CHEMICAL INDUSTRY IN BASLE, OF SAME PLACE.

BROWN DYE.

SPECIFICATION forming part of Letters Patent No. 491,422, dated February '7, 1893.

Application filed August 25,1892. gerinl No. 44,111. (Specimens) Patented in France March '7, 1892, No. 219,925.

130 M5 whom it may concern:

Be it known that we, ROBERT GNEHM and JAKOB SGHMID, citizens of Switzerland, residing at Basie, Switzerland, have invented new 5 and useful Improvements in the Production of a Brown Coloring-Matter or Dye-Stuff, (for which we have received Letters Patent in France, No. 219,925, dated March 7, 1892,) of which the following is a specification.

[ Ourinvention is based upon the observation that the insoluble products in water which are obtained by combination of meta or para-diazo-benzoic acid with the so-called Bismarckbrown can be converted into readily soluble x alkaline salts with the aid of potash or soda, thus forming useful brown coloring matters which dye nnmordanted cotton.

The following is an example in which way our invention maybe carried outin practice:

10.5 kilos of13isn1arckbrown J (product obtained by the action of two molecules of nitrous acid upon three molecules of hydrochlorate of lneta-phenylenediamine) or Bis- IlltltiliblOWB R (analogous derivative from meta-toluylene-diainine) are dissolved in fifty liters of "water. The solution is cooled with ice and introduced into a cold solution of nieta-diazobenzoic acid obtained by a mixture of 5.2 kilos of meta-amido-benzoic acid 2.6 kilos of sodium nitrite and eighteen kilos of muriatic acid. A brown substance is separated; its formation becomes complete as soon as a solution of twenty kilos of crystallized acetate of sodium is added. After stirring during several hours the product is filtered off, Washed and pressed. In introducing this residue into a dilute Warm solution of potash or soda, the dye-stufi dissolves and is precipitated from the solution with common salt in the form of brown flakes. It is filtered, 4o pressed and dried and forms now a dark brown powder easily soluble in water. It dissolves With difficulty in alcohol with a brownorange color and is insoluble in benzene. It

is soluble in concentrated sulphuric acid from which solution it precipitates by addition of water.

The new coloring matter produces on onmordanted cotton in a neutral or alkaline bath dark yellow-brown shades. 5o 1 What we claim as new and desire to secure by Letters Patent is:

The new brown dyestult herein described being the sodium salt of an azo derivative of meta-diazo-benzoic acid and the so called Bismarck brown, which is a dark brown powder, insoluble in benzene but easily solublein water, dissolving with ditticulty in alcohol with a brown-orange color and soluble in concentrated sulphuric acid from which solution it precipitates by addition of water.

In testimony whereof we have hereunto set our haudsin the presence of two subscribing witnesses.

ROBERT GNEHM. JAKOB SCHMID.

Witnesses:

GEORGE Grnrono, F. WALTER. 

